What is the differential for this lesion?
Tumours (e.g. germinoma, hypothalamic glioma, CNS lymphoma, pituicytoma, pituitary metastases); infection (e.g. tuberculosis); cellular infiltrates (e.g. Langerhans cell histiocytosis, neurosarcoidosis, lymphocytic hypophysitis).
What is the usual presentation of pituicytomas?
Clinical presentation is either from endocrine dysfunction (amenorrhea, galactorrhea, infertility, diabetes insipidus, panhypopituitarism) or from compression of adjacent structures, typically the optic chiasm. Many are asymptomatic, with the lesion only found incidentally.
MRI of the brain and pituitary demonstrates a sizeable mass centered in the suprasellar and interpeduncular sellar, continuous with the infundibulum of the pituitary gland. It is isointense on T1 and iso- to perhaps slightly hyperintense on T2 weighted images. It enhances vividly. Normal pituitary tissue is seen in the bass of the fossa.